Increasing the levels of dairy ingredients in foods, such as confections, cheeses, spreads, snack bars, cereal bars, and the like, is often desired due to the nutritional benefits that many of the components in dairy ingredients impart to foods. For example, it may be beneficial to increase the amount of whey or milk components in processed cheeses or cheese spreads to increase the levels of protein. Snack and cereal bars are popular with consumers for their ease in providing a convenient and ready-to-eat product. Chewy snack and cereal bars can, in some instances, be more desired by consumers because they resemble the texture and mouthfeel of candy bars. Dairy-based components can be used as binders in snack and cereal bars. It may also be beneficial to provide an increased level of dairy protein in the snack and cereal bars.
However, when using large amounts of dairy ingredients in foods, it also generally results in a corresponding increase in the amount of lactose. For example, whey and non-fat dry milk powders generally comprise about 65 percent and about 50 percent lactose, respectively. Thus, increasing the amounts of these ingredients in foods can also result in corresponding increases in the lactose composition of the resulting foods as well. Increasing lactose in food can, in some cases, have undesired effects on the organoleptic characteristics of the food.
For instance, heating foods containing high levels of dairy ingredients and the corresponding high levels of lactose may cause organoleptic problems due to the solublization of the lactose in the moisture phase of the food. Upon cooling, the lactose may solidify into crystals that can grow into relatively large agglomerates. Such large crystals or agglomerates may result in a gritty mouthfeel or a food that does not have texturally smooth or creamy characteristics. Lactose tends to solublize in moisture when exposed to temperatures of about 130° F. or more. Thus, lactose crystallization tends to be a problem in foods and other comestibles, which desire a smooth and creamy texture, when the dairy ingredients are exposed to temperatures of at least about 130° F., such as during manufacturing, pasteurizing, and/or storage.
In view of this undesired lactose crystallization, it is generally accepted that there is a limit to the amount of dairy components, and thus the amount of lactose, that can be added to dairy-based foods while still retaining a smooth and creamy texture. If dairy components are added at too high a level, then the high levels of associated lactose may result in even a greater tendency for large lactose crystal growth. Large lactose crystals detract from the smooth eating experience of the foods. In order to minimize this tendency, the book PROCESS CHEESE (Vincent L. Zehren) states there is a maximum limit to the amount of lactose that can be included in certain dairy-based foods in order to avoid large crystal formation in the moisture phase. Zehren states that the reported levels of lactose should not be exceeded due to the possibility of causing the formation of large lactose crystals.
In some cases, attempts have been made to minimize lactose crystal growth by purposely forming crystals through seeding, controlling lactose crystal growth via a combination of high temperatures and high shear, or conversion of the lactose to other ingredients. Prior processes that attempt to control lactose crystal size through seeding use lactose micro-crystals. This approach is generally undesired because the lactose micro-crystals complicate the manufacturing process with extra ingredients and process steps. It is often difficult to add the crystals at precisely the correct time and temperature. With lactose seed crystals, good mixing is needed and such additions are difficult to control because the small seeding crystals can melt easily rendering them ineffective as a seed crystal. Prior processes that attempt to control crystal growth through high temperatures and high shear are generally undesired because exposing products with high levels of dairy proteins and lactose to high temperatures can also result in other undesired organoleptic problems due to browning of the dairy components. High shear levels can also increase temperatures to undesired levels. Lactose can also be converted to glucose and galactose through the addition of lactase enzymes. However, these processes are also undesired because lactase enzymes can add additional costs and processing times for the enzyme to convert the lactose to its monosaccharides. Lactose conversion may also impart other undesired organoleptic changes, such as darker colors, increased sweetness, and softer textures.